I. Field of the Invention
This invention relates to implantable, programmable medical devices, for example heart pacemakers and defibrillators. More particularly, it relates to a rights-based security system for regulating the programming of such devices.
II. Description of the Prior Art
Implantable pacemakers have been in use for decades to regulate the beating of the human heart. The earliest pacemakers were nothing more than a pulse generator and a battery designed to deliver electrical pulses to the heart at a fixed rate. Soon thereafter, pacemakers were made available that had two modes of operation. The pacemaker could be switched from one mode to the other by holding a magnet over the pacemaker to actuate a switch.
In the 1960's, throughout the 1970's and into the 1980's, pacemaker manufacturers introduced a variety of pacemaker products that could be programmed through the use of radio frequency or magnetic pulses. Such pacemakers had an operate mode and a programming mode. To prevent inadvertent reprogramming of the pacemaker as a result of ambient electrical or magnetic noise, the circuits for these pacemakers included a “combination lock”. Such pacemakers would only go into the programming mode if the “combination lock” was opened. The “combination lock” typically would only be opened if the correct number of pulses were received within a plurality of discrete time periods.
Until very recently, a patient being treated with a pacemaker would periodically travel to a clinic for assessment and, if necessary, reprogramming. Given the face-to-face interaction between the patient and the medical provider, and the short range transmission of data, security was not a significant issue. With modern data transmission technology, such assessment or program modification can be done from very remote locations. Such assessment and programming could even be done via the Internet.
Given this global data transmission range, the interconnection of devices to the Internet, and the fact that not all people are pure of heart, there is a real need for added security. Life-threatening situations could arise if hackers or anyone with a programmer were allowed to reprogram heart pacemakers or if Internet users were able to infect the programming of a pacemaker with viruses. Similar problems could occur if unauthorized people were permitted to download in an unauthorized fashion history or treatment data from such devices. Without sufficient security, someone knowing the telemetry protocol for retrieval of data from or programming for the implantable device could harm the patient, blackmail the patient, or blackmail the company which supplies the implantable device. There is, therefore, a need to provide a security system which will safeguard pacemakers and other programmable medical devices not only from inadvertent reprogramming, but also from the deliberate efforts of those with evil intent. At the same time, the data must be readily accessible and the device readily reprogrammable in emergency situations, to safeguard the patient's life and health. The present invention provides such a system.